LAC HOST-TREES AND THE BALANCE OF
AGROECOSYSTEMS IN SOUTH YUNNAN~ CHINA 1
CLAUDE SAINT-PIERRE AND OU BINGRONG
Saint-Pierre, Claude (Laboratory of Tropical Botany, URA 327, University of Montpellier, 163rue A. Broussonet, 34000 Montpellier, France) and Ou Bingrong (Research Institute of Resource Insects, Chinese Academy of Forestry, Renmindonglu, Wangdaqiao, Kunming, P.R. China650216). LAC HOST-TREES AND THE BALANCE OF AOROECOSYSTEMS IN SOUTH YUNNAN, CHINA.
Economic Botany 48(1):21-28. 1994. The importance of spontaneous lac host- trees for preserving the fragile agroecosystem of the main lac producing areas of China, located in the tropical part
of Yunnan province, is analyzed. In upland fields, the fire-resistant vegetation consists mainly of these trees. Farmers deliberately preserve young sprouts during the cultivation cycle. This
benefits both soil fertility and lac production. Host-trees, mainly Dalbergia and Ficus, form a range of multipurpose trees which although limited to some ten species allows maximum use of
the heterogeneities of the village territory. Finally, lac host-trees are associated with some environmental values important to farmers. This circumstance contributes to the sustainability of
lac host-tree agroforestry in spite of current problems in the lac market.
Key Words: China; Yunnan; Dalbergia; Ficus; agroecosystem; agroforestry; fallow; fire-resistant; lac; multipurpose tree.
The lac insects (Kerria ssp., Homoptera: Tachardiidae), are scale insects which occur naturally as parasites on various host-plants. They produce lac, a layer of red resin on the branches of
the host-trees on which they settle. World production of lac began to increase at the end of the last century. Almost all of the production was
exported from India, and later Thailand, to Western countries where electrical, aircraft and
military industries required refined and bleached lac which was used as an insulating varnish, but
synthetics began in the 1960s to impose a longterm competition on the natural product (Saha1976).
Farming systems which include lac production have not been described in previous literature.
Most publications on lac date back to the 1960s (Gokulpure, Mehra, and Teotia 1980). According to the Commonwealth Agricultural Bureau
data base, recent literature focuses on the entomology of lac insects and of their predators. Literature describing management techniques, including Chinese literature, focuses on improved plantations.
Received 20 January 1993; accepted 20 June 1993.
Yunnan province, located in the Southwest of
China, is the major lac producing area in the
country. The development of production has been
based on the extension of an agroforestry practice
to a large number of farmers. Spontaneous lac
host-trees have been preserved in upland fields.
Production has been concentrated in small areas
with adequate climatic conditions, in which a
"lac forest" has developed. The area of this forest
is limited to 50 000 hectares as China, although
the third lac producer in the world after India
and Thailand, only accounts for 5% of the world
production with 2000 tons per year (Ministry of
Agriculture 1990; Wu 1988). However, it has an
important regional role, both as a source of cash
income for the populations involved, and in the
ecological balance of the upland farming systems. The extension of such an agroforestry system has not taken place in other countries.
The purpose of our study, beyond describing
this unique system, was to assess whether current
problems in the lac market imposed a threat to
the ecological balance of the lac-producing areas.
The method of assessment was based on agroecosystem analysis (Conway 1985). Interviews
of farmers and extension staff, combined with
the observation of village landscapes in contrastEconomic Botany 48(1) pp. 21-28. 1994
9 1994, by The New York Botanical Garden, Bronx, NY 10458 U.S.A.
22 ECONOMIC BOTANY [VOL. 48
Fig. 1. Location of areas studied.
ing locations, provided a basis for analyzing the
system trends.
Field surveys were conducted in 1990 and 1992
in two major lac-producing counties in Yunnan
province, Mojiang and Jinghong (Fig. 1). These
areas differ in climatic conditions, populations
and the history of lac production. The second
author, Ou Bingrong, one of the few persons who
have been in charge oflac research and extension
in China, also brought his extensive experience,
including data from his early field surveys in the
early 1950s in the same two areas.
LAC INSECTS AND HOST-PLANTS
In Yunnan, lac insects have been identified as
Kerria yunnanensis Ou et Hong, a species distinct from Kerria lacca Kerr. which is the main
species in India (Ou and Hong 1984, 1990;
Varshney 1986). The biology of this species is
similar to that of Kerria lacca (Ou et al. 1984).
Each of two generations per year, May to October
and October to May, starts with a mobile larval
stage lasting two to four weeks. However the
winter generation produces little more than live
larvae for the summer one. During the fixed larval stage, larvae settle on branches in large numbers, up to 200 per cm 2. Finally winged male and
fixed female adult forms appear, the latter becoming embedded together with their eggs in the
lac they exude.
The optimum annual mean temperature for
lac insects ranges from 18 to 20~ but the insects
can survive a mean minimum temperature of
I~ in January. The area of production extends
to 24 ~ North latitude in the southwest part of
Yunnan, which is protected from winter cold
waves from northern China by mountain ranges.
Production is localized in sheltered valleys below
1200 masl, where conditions of bright sunlight,
without wind, favor dissemination of mobile larvae on the branches of the host-tree and allow
higher lac yields.
1994] SAINT-PIERRE & OU BINGRONG: LAC HOST-TREES IN CHINA 23
Lac insects are hosted by more than 300 local
plant species, but only some ten plant species
yield enough lac to be used for production (Appendix). Most of them are distinct from the species generally used in India and Thailand. Two
groups of lac host-trees can be defined: the first,
with Dalbergia obtusifolia, is adapted to dry conditions but sensitive to low temperatures, the
second, with Dalbergia szemaoensis, withstands
lower temperatures but requires more water.
In Mojiang, D. obtusifolia is found in small
numbers in remaining patches of lower subtropical forest together with Schima wallichii (DC.)
Korth., Phyllanthus emblica L. and Pinus kesiya
Royle ex Gordon var. langbianensis, a forest
similar to the one found in other regions south
of the Himalayas (Dobremez 1972). In the 1950s,
D. obtusifolia was abundant in the savannas which
succeeded swiddening.
As its Chinese name, "as strong as cow ribs,"
suggests, D. obtusifolia is able to resist drought,
fire and lac insect parasitism. With coarse leaves
falling between February and May and a high
osmotic pressure in its tap root, it can stand the
six-month dry season on the sandy soils of upland fields (Chen and Hou 1980). The trees also
have a thick bark and can resist light fires on
bush fallows. Young sprouts regularly grow from
the upper part of the roots even if trees are burnt
in heavier fires or cut down.
Several characteristics of these sprouts make
D. obtusifolia a fire-resistant tree with little invading power. Young sprouts grow in limited
number on each tree. They remain non-woody
with tender leaves for several months during
which they are easily destroyed by weeding tools
or browsing animals. Two or three sprouts from
the same tree will grow into trunks joined side
by side, forming a single crown with a vertical
growth habit (Fig. 2). The radius of the crown is
limited, as is the one of the root system (Appendix).
Among other spontaneous host-plant species
frequent in swiddens, Eriolaena spectabilis also
has a tap root and a bark which make it a fireresistant tree, whereas Ficus semicordata seeds,
propagated by birds, find favorable conditions
in swiddens after fire. Dalbergia fusca, found in
large numbers in swiddens in Jinghong, shares
D. obtusifolia characteristics.
Dalbergia szemaoensis has contrasting characteristics. With leaves which do not become
coarse and a superficial root system, it requires
more water than other species. It is spontaneous
on northern slopes up to 1400 masl, and in less
dry parts of the village territory, such as near
streams, together with Ficus altissima and F. racemosa.
LAC USES AND PRODUCERS
Lac has been reported in Chinese literature
since the third century A.D. It was a minor forest
product gathered by various highland ethnic
groups, who used it as barter with the lowland
people (Ou and Hong 1984). Lowland people in
the area are the Tai (the Lu of Laos), belonging
to the Thai language family. They add lac to betel
chew, and use lac to dye clothes such as Buddhist
monks' robes. Highland ethnic groups used lac
as tooth dye, as a varnish for dishes, as a resin
to fasten knife blades into handles, and as a medicine against hemorrhage. The latter two uses
persist in present time.
Lac in China began to be sold in the 1920s in
small quantities through Yunnanese caravan trails
reaching both British Burma and French Indochina. After 1962, lac production was developed
for national needs. Seventy percent of the Kerria
yunnanensis resin which is strongly red, is used
unbleached as a varnish for furniture in China
(Duan 1991).
In the Southern part of Mojiang county, the
major producing area in Yunnan, the entire population of 70 000 is Hani, a large Tibeto-Birman
ethnic group (the Akha of Thailand, belonging
to the Loloish language family), numbering 1
million people in China. Although the Hani often
have a migratory settlement pattern, villages in
Mojiang settled long ago. The population density
approaches 75 inhabitants per km 2, with a birth
rate reported to be 3.5% (Li 1987). Today, the
farming system is based on swiddens with bush
fallows. The duration of fallow has been reduced
to three years on average, with three years of
cultivation, one year of upland rice followed by
two years of corn, the staple food. All the population is involved in lac production, which was
extended in the mid-1960s.
The Jinuo are a small Tibeto-Birman ethnic
group numbering l0 000 people, located in the
Jinuo mountains of Jinghong county. Little is
known about the origin of these people, and
whether they too belong to the Loloish language
family has been questioned (Du 1985). Their
farming system is based on rotational shifting
cultivation, with long fallows and settled village
24 ECONOMIC BOTANY [VOL. 48
Fig. 2-4. Fig. 2. Dalbergia obtusifolia trunks formed by several sprouts. Fig. 3. D. obtusifolia in a swidden.
Fig. 4. D. obtusifolia in rows. All photographs taken in April 1992 in Honghuashu village, Mojiang county.
territories, which is an unusual practice among
Tibeto-Birman groups. This system is still going
on despite growing population densities (Yin
1988). In Jinghong, only the Jinuo take part in
lac production, whereas other highland people,
including Hani, do not. The Jinuo probably had
easier access to the Yunnanese caravans to which
some villages sold Puer tea.
LAC PRODUCTION PRACTICES
In both areas studied, the villages producing
lac are located in the upper part of the mountain
slopes, from 1000 to 1500 m in altitude (Wu
1988). The village territories feature areas with
distinct agroecological conditions. Soil water
during the long dry season is the major variable
but orientation, degree of slope and altitude are
important factors. Village territories are organized in successive belts. Forest belts which surround the houses are themselves surrounded by
permanent fields. Most swiddens are located
lower than the houses between 900 and 1200 m,
and rice fields are situated in the valley at 800
m. Trees are only found in the forest belts and
in the swiddens, where spontaneous trees grow
in both cultivated and fallowed fields. Many of
them are lac host-trees. Dalbergia szemaoensis,
Ficus altissima and F. racemosa are mostly found
in the forest belts, D. obtusifolia Prain are dominant in Mojiang swiddens whereas D. fusca is
dominant in Jinghong swiddens.
Host-trees in upland fields are closely associated with swiddening cultivation (Hou, Chen,
and Chen 1985). Fires at the beginning of the
cultivation cycle temporarily eliminate herbaceous competitors of young tree sprouts. During
cultivation, weeding reduces such competition,
and farmers preserve some of the more vigorous
sprouts by avoiding them when ploughing and
hoeing, and they protect both crops and trees
from cattle.
Before lac production was developed on a large
1994] SAINT-PIERRE & OU BINGRONG: LAC HOST-TREES IN CHINA 25
scale, farmers in Mojiang cut down most trees
at the beginning of each cultivation cycle, whereas farmers in Jinghong preserved some of the
host-trees (Ou 1973). Because of this practice, a
research and extension program was set up in the
province in order to preserve host-trees. Today,
lac is raised on trees from the fifth year on and
a lac production cycle equals two cultivation cycles. The density of trees is limited to 150-200
per hectare in upland fields in order to preserve
grain yield (Fig. 3). Families with more land
available keep a high density of 300-450 trees
per hectare in fields further from the houses. A
new pattern was observed in villages needing to
transform swiddens close to the houses into permanently cultivated fields. Here farmers had preserved spontaneous D. obtusifolia sprouts in rows
so that, after eight years, the trees formed belts
(Fig. 4).
Although trees reduce the amount of sunlight
available to crops growing next to them, on a
longer term, according to observations and interviews, they have an overall positive effect on
fertility. Shade provided by trees limits the growth
of graminaceous weeds. The crown reduces the
impact of rain-drops on the soil while the roots
stabilize the soil on steep slopes. The nitrogenfixing nodules of D. obtusifolia and D. fusca are
assumed to provide some nitrogen for the crops,
and probably have a positive effect on the regrowth of vegetation during the fallow period.
Because tree sprouts are protected from the
beginning of the vegetation cycle, they provide
more shade and biomass during fallow. When
the fallow period starts, new sprouts are already
three years old and 2 to 4 m high, while at the
end of it they are six years old and reach 5 to 8
m. In Mojiang, in swiddens with more degraded
conditions, fallows are dominated by Chromolaena odorata (L.) R. M. King and H. Robinson,
Asteraceae, which yields a limited amount of
biomass. Most of the biomass comes from D.
obtusifolia. In Jinghong, under less degraded conditions, shade from host-trees contributes to the
regrowth of diversified tree species.
Other host-tree species have a horizontal
growth habit, or lateral roots, or both, so that
farmers only preserve young trees when they grow
at the limit of a field or along paths. The limitation of soil erosion by the root systems is needed all the more in such places.
Lac insects benefit from the association of hosttrees with upland crops. They find warmer and
drier climatic conditions in winter in upland
fields. South orientation of slopes and a lower
density of trees than that of the forest allow more
light penetration. Swiddens are located just above
the temperature inversion level, a specifically important factor in the region. At a lower elevation,
heavy fogs from November to January induce
cool temperatures until noon. At a higher elevation, frost occurs every year and wouldldamage lac insects as well as new host-tree leaves
(China Tree Flora 1981).
Management practices are extensive and are
aimed both at ensuring a sus[amable lac production and at preservin~ [he yield of adjacent
crops. Farmers increa~ ~e sp6htan~t~sjl~ulation of lac insects by tyinWl~~'sm~
branches covered with live l~rvae ~bm ~he witter generation to branches of trees producing the
summer generation. Research results on protection against insect predators have not been applied, and no protection is practiced. Trees are
regularly trimmed for harvesting lac, so that the
radius of the crown and the vigor of the trees are
reduced, thus diminishing their negative effect
on crops. Finally, since lac insects prefer to settle
on three-year-old branches, two thirds of the trees
are not used for lac production while branches
grow again after having been pruned (Ou and
Hong 1984). Half of the remaining trees are only
used to raise the winter generation. As a result,
six trees should be kept in order to have one
productive tree in summer. However, live larvae
are often not produced by the farmers but provided by the extension department.
ROLES OF LAC HOST-TREES
IN THE AGROECOSYSTEM
Lac was the only source of cash in most villages
in South Mojiang and in the Jinuo mountains
until recently. An average family of 6.5 persons
farming two hectares could harvest 100 kg, i.e.,
1 to 3 kg of dry lac on 50 of their 300 trees every
year, and sell it for 300 yuan (100 yuan = 17
U.S. $ in 1992), the equivalent of two pigs. This
was a significant sum compared to the very low
monetary income in the area, however, lac sales
were not regular. Lac host-trees in the highland
farming systems have the same role as cattle.
They make up a capital which can be conveniently turned into cash when needed for major
family events, or when a market opportunity
arises. Lac host-trees are locally called "trees that
turn into money." A family could inoculate all
26 ECONOMIC BOTANY [VOL. 48
trees at a time and sell 600 kg six months later.
Unfortunately this, together with climatic accidents, has resulted in overproduction cycles and
price fluctuations, as in India (Saha 1976). Marketed quantities in Mojiang have repeatedly oscillated within five or six years between 100 and
800 tons per year. Farm gate prices for lac rose
to 8 yuan/kg in 1985 and locally fell as low as 1
yuan in 1989. They had not recovered yet in
1992 as the local Chinese market for red lac encountered problems linked to a lower demand
and more regional competition.
When there is no need or no opportunity for
this cash income, lac host-trees remain a live
capital and are used for their various other purposes (Appendix). Timber is a much valued
product now that building a house with a tile
roof has become the main exterior sign of wealth.
Labor during the rainy season is the basic limiting factor in farming systems of both areas studied. Lac host-trees allow both a cash and a noncash income without much labor inputs. It takes
five days to harvest 50 trees. Growing trees for
lac also saves labor in collecting timber, fuelwood, fodder, and fruit since both trees inside
fields and trees kept close to houses and paths
are easily accessible. Timber with a small or a
medium diameter, ready to use, is also available
(one of the names of D. fusca is "fence tree").
Producing lac also saves handweeding labor. A
smaller equivalent area of land needs to be weeded because both grain and cash crops are grown
on the same plot. In addition, the expansion of
gramineous species, which are the most difficult
to weed by hand, is limited. While these factors
are found in any association of crops with trees,
a major advantage of lac host-trees is that they
are spontaneous multipurpose trees, whereas
planting tree seedlings is labor-intensive, expensive and uncertain because of the long dry season
(MacDicken and Raintree 1991). Farmers in both
areas studied were deeply aware of this specificity
oflac host-trees. They pointed out that they never had to plant any trees because trees in their
villages grew by themselves.
Lac host-trees contribute not only to the economic balance of the farming systems but also
to the ecological balance of the producing areas,
which is particularly fragile. Host-trees yield timber, fuelwood and forage since they are regularly
pruned. Trees in swiddens have a density sufficiently high to contribute as noted above to the
preservation of soil fertility, especially because
more trees are preserved than are harvested each
year. In forest belts around villages, trees with a
horizontal growth habit such as D. szemaoensis
and large old Ficus such as F. altissima and F.
racemosa protect springs and streams and provide shade. A small range of tree species, with a
single opportunity for cash income, i.e., lac, is
enough to preserve trees in the various parts of
the agroecosystem.
The large Ficus species are viewed as sacred
trees by all ethnic groups in the region, both the
Buddhist groups in the lowlands and the animist
ones in the highlands. Traditional rules prohibiting their being cut down have been recorded
among the Jinuo. For these rotational swiddeners, preserving the old sacred trees was a condition for insuring prosperity to the village (Du
1985, Yin 1988). Farmers said that harvesting
lac from them, however, was allowed. It must
be noted that D. szemaoensis grows in the forest
belts together with these Ficus. Furthermore D.
szemaoensis is one of the tree species with the
highest regeneration power in the area. Farmers
said that it had "roots which never die." It is the
only host species called "lac tree" in the various
local languages and it must have been the main
source of lac for village handicrafts before production was developed on a larger scale. While
no ritual use oflac was recorded during the study,
interviews lead us to the assumption that farmers
draw a link not only between soil fertility and
sacred trees, but also with lac insects and their
host-trees. Unfortunately this could not be verified by interview because most sacred trees have
been cut down during the cultural revolution in
the 1960s, and where they were preserved neither
Hani nor Jinuo farmers spoke openly about their
sacred trees.
Farmers have sold very little lac since 1988.
However, in the two areas studied, most of them
have carefully kept their host-trees. In Mojiang,
this contrasts with reports that Hani traditions
of preserving the environment have dramatically
decreased in the 1960s (Mao 1991).
Conversely, attempts by researchers to develop cultivation of important lac host-plants have
met with little interest on the part of farmers.
Cultivation of Flemingia macrophylla has been
successful in trials here as it has in other countries
(Sohan et al. 1976). This fast-growing species
can be used to enrich fallows, but it has to be
planted. Pigeon pea (Cajanus cajan) too must be
planted but farmers have adopted it to some ex-
1994] SAINT-PIERRE & OU BINGRONG: LAC HOST-TREES IN CHINA 27
tent probably because, in addition to raising lac
insects on it, the grain is used as fodder. Croton
oblongifolius plantations in upland fields and Ficus racemosa roadside plantations have been implemented through extension programs.
CONCLUSION
Spontaneous fire-resisting host-trees in lacproducing regions of Yunnan province are plant
resources of high value. These multipurpose tree
species give farmers both a cash income and various non-monetarized yet essential products, with
limited labor inputs. They are also the only species in the agroecosystems likely to play a positive role in preserving the soil fertility. As opportunities for other cash crops such as tea, coffee
and rubber-trees are being developed, and as the
balance of agroecosystems becomes an important issue in these areas, the major contribution
of lac host-trees in the future might not be the
cash income they allow but their contribution to
maintaining this balance.
Because the interest that farmers take in their
lac host-trees is not only economic but also linked
to their own system of values towards their environment, there are good prospects that the trees
will continue to be preserved even if problems
in lac marketing remain unsolved. Should farmers go back to their former practice of cutting
trees at the beginning of the cultivation cycle,
tree sprouts will still grow again and contribute
to the sustainability of the farming system.
APPENDIX: MAJOR LAC HOST
TREES IN YUNNAN
The literal translation of Chinese names is mentioned in brackets when the meaning is related to farmers' practices. The first Chinese name mentioned is the
one farmers use most often. Hani names were already
out of use in Mojiang county in the 1950s. Jinuo names
were still in use in 1990.
Botanical name~principal Chinese name and translation/other Chinese names/HANI NAME/JINUO
NAME/growth habit and adaptation to the dry season/
uses other than lac production/source of introduced
species.
FABACEAE
Cajanus cajan (L.) Huth/mu dou (wood pea)/up to
4 m, lac harvest on 2nd and 3rd years/grain and leaves
used as pig fodder; medicinal root.
Dalbergiafusca Pierre/hei xin shu (black-heart tree)/
shanlan shu (fence tree), niujiao shu (cow-horn tree)/
SE NA (Jinuo and Hani: fibrous bark)/vertical growth
to 12 m, crown radius 2 m maximum; radius of root
system to 6 m; coarse leaves/quality timber, wood for
fences.
Dalbergia obtusifolia Prain/niuleiha (cow's ribs)/niu
jin mu (cow's nerve wood)/DEJIU ABO, PALONG
BU (Hani)/vertical growth to 7 m in 5 years, crown
radius to 2 m; deciduous coarse leaves/fuelwood, timber.
Dalbergia szemaoensis Prain/yang qing (green rice
seedlings)/ya yang shu (tree turning rice seedlings into
green), zigengshu or zijiaoshu (lac tree)/MENO ABO
(Hani: lac tree)/JIE PLA, JIE ZI (Jinuo)/horizontal
growth to 8 m in 4 years, crown radius to 7 m; lateral
root system, radius to 10 m/some timber; leaves used
as green manure.
Flemingia macrophylla (Willd.)Merr./daye qianjinba/up to 4 m in 1 year, 6 m in 3 years/fodder, fuelwood,
green manure; medicinal root/introduced from L/ichun
county (Yunnan).
EUPHORBIACEAE
Croton oblongifolius Roxb./jinggu badou (Jinggu
county Croton)/vertical growth to 7 m; crown radius
1 m; radius of root system 3 m/introduced from Jingu
county (Yunnan).
MORACEAE
Ficus altissima B1./gao shan rong (high mountain
ficus)/NIU MO (Jinuo).
Ficus racemosa L./malang shu/TONG HONG
(Hani)/DU LE (Jinuo)/figs used as pig fodder.
Ficus semicordata Buch.-Ham./jisu guo (chicken crop
fruit)/SIO GU, AGO ASI (Hani)/SE JIU (Jinuo)/horizontal growth habit, crown radius to 7 m; lateral root
system, radius to 7 m/fuelwood; figs much eaten; leaves
used as pig fodder; medicinal root.
STERCULIACEAE
Eriolaena spectabilis (DC.) Planch./huosheng shu
(lighter tree)/MAI LI (Jinuo)/vertical growth to 7 m
in 5 years, crown radius 1.5 m maximum; both tap
root and lateral root system; deciduous leaves; both
lateral and tap root system, radius up to 6 m/timber;
bark fibers used for ropes; leaves used as pig fodder.
ACKNOWLEDGMENTS
The 1992 field study in Mojiang county was organized with the institutional support of Yunnan province Commission of Science and Technology and logistical help from Mojiang Forestry Bureau. The 1990 field
study in Jinghong county was made possible with the help of Xishuangbanna tropical botanical garden, Kunming Institute of Botany, Academia
sinica.
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